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Technical

surfer: Lance Carleton
photo: 18seconds/Andy Morris

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Technical

Technical details for our fins

This section discusses technical details related to our fins and their construction.

There are a number of technical details that go into the manufacturing of our fins. These include things like the different types of materials and manufacturing techniques.

Additionally, there are a number of design advances that we have incorporated into our fins. These include things like the different types of foils and enhancements to the fin profile.

HANALEI FINS are manufactured for all of the major fin bases in use, these are also introduced here.

Technical

FLIP TIPS

FLIP TIPS are the term we use for the unique design of the tip extensions added to some of our fins. These tips add significant performance enhancements to the fins.

WTF, XTC, DS, and WS2 designs utilize these tips.

Example of FLIP TIPS

FLIP TIPS are set at between 14º - 16º angle (outboard) to the blade of the fin and provide a couple of important attributes to the performance of the fin.

Due to the hollow foils on the inside faces of the fins design that utilize these tips. The addition of the flip tip improves the efficiency of these inside foils. This is accomplished by allowing the hollow foil to extend to the tip. Making the unflipped portion of the fin a lot more efficient.

The tips themselves also have a slight hollow foil on the inside face to improve their efficiency and to better couple with the foil in the blade.

One of the most important attributes of these tips is how they allow the board to transition through turns. If you visualize these fins in use you can see that as the board transitions more to the rail the tips of the engaged fins become more vertical in the water.

Not only does this improve the feel of the fin, but it more importantly helps the board come around during the turn, as it provides something to pivot around. All of this is done without losing any speed!

The illustration above shows the WF2-S fin and the shape of the flip tips. These tips do not alter the outline of the fin and are only noticeable when viewed from the front or back.

Very hard to describe how they feel and work but once you try them there is no going back, there is something magical about them!

Currently, the following HRD-KORE fins feature FLIP TIPS - WF2-S (Split keels front fin), DS-400, WTF-425 and XTC range.

FLIPTWO TIPS

FLIPTWO is the term used for our refined tip extension design. These tips add subtle performance enhancements to the fins.

QFT, Q5, WS2, and F8 designs all utilize these tips

Example of FLIP TIPS

FLIPTWO tips are flipped between 4º – 6º angle (outboard) to the fin's blade and provide a couple of essential attributes to the performance of the fin.

Due to the hollow foils on the inside faces of the fin designs that utilize these tips, the addition of the flip improves the efficiency of the inside foils. This is accomplished by allowing the hollow foil to extend to the tip. It makes the unflipped portion of the fin a lot more efficient.

The tips also have a slight hollow foil on the inside face to improve their efficiency and better couple with the foil in the blade. Compared to the older versions, the newer tips are significantly thinner, reducing the chance of cavitation.

One of the essential attributes of these tips is how they allow the board to transition through turns. If you visualize these fins in use, you can see that as the board transitions to the rail, the tips of the engaged fins become more vertical in the water. Not only does this improve the fin's feel, but it, more importantly, helps the board come around during the turn, providing something to pivot around. All of this is done without losing any speed! This newer, refined version is slightly more subtle than the previous versions but still has similar characteristics.

The photo shows the WF2-400F fin and the angle of the flip tips. These tips do not alter the fin's outline and are only noticeable when viewed from the front or back.

This newer version enables this tip style to be added to some of our CNC-machined fins. The older style tips would not have been possible due to the panel thickness required to accommodate the flip.

Currently, the following CNC fins will feature FLIPTWO tips – WF2-400F (Split keels front fin), QFT-500, QFT-425, Q5-600, Q5-550, Q5-500, Q5-475, Q5-450, Q5-425, and F8 range.

TECHNICAL DETAILS

About foils and construction materials

Foils

Foils play a crucial role in the design of a fin and can dramatically impact the performance. Most of our foils are loosely based around the NACA 00 series of wing sections ideal for fins.

HOLOFOILS

HANALEI FINS are unique in that we have perfected the use of inner hollow foils on the inside faces of most of our fins. We use these foils to increase performance and efficiency. In many cases, we also couple these foils with twists and turns in the trailing edge of the fin to better manage the ejection of water from the foils. These foils dramatically impact the overall performance of our fins, but in particular, on the speed! Our term for these inside foils is HOLOFOILS!

PHAT FOILS

PHAT FOILS is our name for the thicker foils deployed on some of our fin designs. The fin's efficiency is dramatically improved by making the foils a lot thicker. Plus, on fins that also use our FLIP TIP technology, the PHAT FOILS allow a much better transition from the fin's blade into the tips.

Currently, these foils are only available on our custom fins, but some of the newer designs that will go into production this year will feature these foils.

FIN BASES

Many different fins systems are available in the market, many with unique base styles. HANALEI FINS supports the three primary bases - GEARBOX (our base is also compatible with ProBox), DUAL TAB, and FUTURES, for side fins, and the REGULAR base for normal longboard fin boxes.

GEARBOX

The GEARBOX base is used in our fin system GEARBOX, and it features a full base for a solid feel and greater strength. The GEARBOX base also features vee notches where the screws land that allows the fin base to be forced down into the box when tightened, creating a compression fit.

The GEARBOX base is also compatible with the ProBox Fin System.

The DUAL TAB base is widely available due to many boards with twin plugs installed. The DUAL TAB base also fits in the GEARBOX fin box. These bases are designed to break under load and therefore tend not to be very durable, breaking at inopportune times. the other problem with these bases is the tendency to flex in the base instead of the fin. This is due to the narrow interface between the fin base and the box.

Due to its box design, the FUTURES fin base is much longer than other bases. Due to the nature of the fin box design, the cant angle is built into the base of the fins instead of into the box. This makes making fins for this system complicated, especially if they are custom fins, as the angle has to be machined into the fin base. Fit is critical for these bases as there are no means to tighten them if they are loose.

These bases can also be much heavier because they are almost double the length of a GEARBOX or DUAL TAB base. This is why you commonly see these bases heavily machined to lighten them up.

The REGULAR base is the standard longboard center fin style base. Designed to fit in most modern center boxes.

Manufacturing Techniques

CNC Machining

Machining a fin on a CNC machine

Our newest fin construction methodology uses a CNC machine to create fins out of solid fiberglass panels. The method is the closest we can get to our hand-foiled fins. The process involves making a sample fin, which is then digitized into a 3D file. This file is then used to generate code that drives the CNC machine, allowing it to reproduce exact copies of the sample fin.

The process involves first laying up panels of solid fiberglass that are then placed in the machine. The thickness of the panels varies depending on the size and thickness of the fin. One side of all the fins on the panel is machined first. Then the panel is flipped over and the other side is machined. It is a slow process but it produces precise fins.

As these are exact copies of the original they have the same flex and strength characteristics!

RTM Molding

RTM molding is one of the most predominant methods for molding fins. It stands for Resin Transfer Molding. The fabrics and core that make up the fin are laid dry into a mold. The mold is then closed, and a vacuum is used to draw resin through the mold, wetting out the materials. Using a vacuum also draws all the air out of the laminate eliminating air bubbles.

RTM molding is much more cost-effective and less wasteful than the standard method of foiling a fin out of a solid fiberglass panel. Because a mold is used, it also makes it easier to manufacture more complex shapes consistently.

We are slowly moving away from this construction method to the CNC machining options as it gives us greater flexibility.

Materials

Fins can be made out of a wide range of materials, but these are some common standard materials, with fiberglass being the most prominent one. RTM molded composite fins use a combination of these materials.

Fiberglass

Fiberglass forms the bulk of a fin construction and is applied on either side of the core material in our HRD-KORE construction method. The typical fin can have as many as 27 layers of fiberglass to provide strength and some flex.

Custom fins are made of panels built into solid sheets of fiberglass and resin. The number of layers can vary from 30 to 40 layers. This is the standard material for hand-foiled fins.

Carbon Fiber

Carbon fiber is strong and stiff for its weight making it perfect for base stiffening. Employed in the base area of the fin to add stiffness and strength, it is applied to both sides of the fin as an outside layer visible in the finished product.

SORIC

Soric® is a conformable flow media for resin infusion. This product features unique hexagonal flow channels across a carrier sheet, creating a steady, even resin front. It forms the core for the fin and reduces weight by reducing the layers of fiberglass needed to construct the fin.

G10

G-10 glass cloth reinforced epoxy natural is typically yellowish to light green color. The most versatile all-around laminate grades are continuous glass woven fabric impregnated with an epoxy resin binder. These panels are made under high pressure, so the panel has no air, and the resin-to-fiber ratio is very high. This makes for an incredibly strong panel.

Because these panels are manufactured, it is much simpler for a fin manufacturer as one purchases the panels and then cut fins out of them as needed. The panels are much more expensive than a standard fiberglass panel, but they are worth it for their strength.

We occasionally use pieces of G10 combined with regular fiberglass panels to make DUAL TAB fins that need more base strength.

Advanced fin designs to take your surfing to the next level.

OFFICES

Primary office locations for HANALEI FINS - Australia and Hawai'i (USA). Contact info is provided here, but the preferred contact method is through the contact form on this site.

+61 2 4339 9580

+1 808 639 5303

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